Created attachment 353425 [details] [review]
vaapiencode: Fix the hardcoded range of quality level

Hm actually there is a bit of problem here.!
All 1.8.x series driver are returning a max val of 8 and https://github.com/01org/intel-vaapi-driver/pull/194/files patch going to change it to 7.

For gstreaemr-vaapi the below codeo will case issues
GST_VAAPI_ENCODER_QUALITY_LEVEL (encoder) =
        gst_util_uint64_scale_int_ceil (GST_VAAPI_ENCODER_QUALITY_LEVEL
        (encoder), quality_level_max, 7);

May be it is more better to use 8 in the gst_util_uint64_scale_int_ceil(),
but encoder property should advertise the max val as 7.

Otherwise,

Users having driver-1.8.x are going end up in trouble by setting 8 as quality level:
8*8/8 = 8

On the other hand, if we keep 7 as hard-coded value as in patch,
Users having driver-1.8.x are going to end up in trouble by setting 7 as quality level:
7*8/7 = 8

Created attachment 353494 [details] [review]
libs: encoder: Fix the quality level clamping

Change the hard-coded range of quality-level from {1-8} to {1-7},
since it is the range Intel Open source driver supports.
Also perform the range clamping only if the user provided
quality-level is greater than the max-range suppored by the driver,
because there could be non-intel drivers giving lower value than
he hard-coded max value 7.

Anyway user won't be able to request for a value more than 7 since we set the property range to a hard-coded magic number 7.

eg: let's say driver query returns 2 as max range and user requested for a quality level 3.
The previous code(with out patch) will set the quality as ceil (3 * 2/8) = 1 which is wrong.

I think we just need to set the quality-level to max-range returned by driver(if user requested quality-level is greater than driver-max-range).

Indeed, doing a clamp was my first option, but then I thought it was better to do a scaling value to the drivers' maximum.

I'm going to change a bit the code to reflect the clamping, by using CLAMP :)

Attachment 353494 [details] pushed as 595f8b7 - libs: encoder: Fix the quality level clamping